1. Department of Neurosurgery, Kentucky College of Osteopathic Medicine, University of Pikeville, Pikeville, Kentucky, United States.
2. Department of Neurosurgery, School of Medicine, University of California, Irvine, California, United States.
3. Department of Neurosurgery, School of Medicine, Mercer University, Macon, Georgia, United States.
4. Department of Neurosurgery, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland, United States.